@peterdrake diagnostically, it might be useful to try 'sudo shutdown -h now' to see where the problem lies. If that works, it suggests the desktop environment's power button isn't triggering the OS to shutdown. If it doesn't, it implies that your OS can't talk to the hardware, so you're maybe missing some firmware or compatibility layer.
@khird @peterdrake
I run into this issue all the time with a variety of distros and machines. "telinit 0' almost always works (or whatever the systemd equivalent is).
Sometimes a shutdown process will pause for 30 secs or a few minutes before shutting down. It should show a countdown timer or give some other indication when it does that, but if the display gets zapped you may not see that; so you might try just waiting 10 minutes to see if it eventually shuts down.
Also, just pushing the power button once will often initiate an orderly shutdown.
@aebrockwell